APB2 peripheral clock enable register
| SYSCFGEN | System configuration controller clock enable |
| TIM9EN | TIM9 timer clock enable |
| TIM10EN | TIM10 timer clock enable |
| TIM11EN | TIM11 timer clock enable |
| ADC1EN | ADC1 interface clock enable |
| SDIOEN | SDIO clock enable |
| SPI1EN | SPI 1 clock enable |
| USART1EN | USART1 clock enable |